<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        /*  1 + 1 + 10 =12  放上面不生效，放下面12下一个才生效*/
        div p:hover{
            color: aqua;
        }


        /* 10 + 1 =11 */
        .box p{
            color: red;
        }
        /* 1 + 1 = 2 */
        div p{
            color: blue;
        }
        /* 1+1+10=12 */
        div p.title{
            color: yellow;
        }


    </style>
</head>
<body>
    <div class="box">
        <p class="title">我是p标签</p>
    </div>
</body>
</html>